An increasing number of recent-year electronic apparatuses and the like are provided with batteries there inside and are occasionally used outdoors. Many of portable electronic apparatuses, such as mobile terminals, intended for outdoor use are waterproof so as to withstand rain. Not only such portable electronic apparatuses but also many of apparatuses for outdoor use are waterproof.
FIG. 1A is a perspective view of a mobile terminal 1 as an exemplary waterproof apparatus 1. While the mobile terminal 1 as an exemplary waterproof apparatus 1 will be described hereinafter, the two are denoted by the same reference numeral. Note that the waterproof apparatus 1 is not limited to a portable electronic apparatus such the mobile terminal 1 and may be a stationary apparatus intended for outdoor use. The mobile terminal 1 includes a display unit and an operation unit. A case 2 of the mobile terminal 1 has a communication hole 3 in which connection terminals for external devices such as a headphone and a storage medium are provided. In general, as illustrated in FIG. 1B, the communication hole 3 is closed with a cap 4 that is attachable to and detachable from the case 2. If the mobile terminal 1 is waterproof, the cap 4 closing the communication hole 3 serves as a waterproof cap 4 having a water-stopping function. A configuration of the waterproof cap 4 according to a comparative technique will now be described with reference to FIGS. 1C to 1E.
FIG. 1C is an enlarged sectional view of the waterproof cap 4 illustrated in FIG. 1B that is taken along line IC-IC. FIG. 1D is a side view of the mobile terminal 1 illustrated in FIG. 1A. FIG. 1E is a sectional view of part of the mobile terminal 1 illustrated in FIG. 1D that is taken along line IE-IE, and illustrates a configuration of the waterproof cap 4 according to the comparative technique.
The waterproof cap 4 includes a flat portion 7 and a peripheral wall 8. The peripheral wall 8 is a continuous wall projecting from the flat portion 7. An O ring 9 serving as a water-stopping member is fitted around the peripheral wall 8 and near the tip of the peripheral wall 8. The O ring 9 is typically an elastic member made of rubber or the like. The communication hole 3 provided in the case 2 has an inner wall 3A with which the O ring 9 is brought into contact and a contact portion 6 with which a tip 8T of the peripheral wall 8 of the waterproof cap 4 is brought into contact. The inside and the outside of the case 2 is continuous with each other through a communication portion 5. In a state where the communication hole 3 is closed by the flat portion 7 of the waterproof cap 4, the O ring 9 is pressed against the inner wall 3A of the communication hole 3 and is thus compressed as illustrated in FIG. 1E. Hence, the O ring 9 exerts the water-stopping function, and the waterproof cap 4 is less likely to come off the communication hole 3.
The waterproof cap 4 according to the comparative technique exerts the water-stopping function by using the O ring 9 that is compressed in a direction orthogonal to a direction in which the waterproof cap 4 is fitted into and removed from the communication hole 3. Hence, when the waterproof cap 4 is fitted into and removed from the communication hole 3, the waterproof cap 4 is slid with the O ring 9 being compressed. Therefore, the O ring 9 tends to be damaged with scars or the like after repeated fitting/removal of the waterproof cap 4. Consequently, the water-stopping function of the case 2 may be deteriorated. To solve such a problem, the O ring 9 may be compressed in the same direction as the direction of fitting/removal of the O ring 9 into/from the communication hole 3. To realize such a structure, however, the strength of the flat portion 7 of the waterproof cap 4 has to be increased or the O ring 9 has to be held by another member. Consequently, the size of the apparatus may increase, or the design of the apparatus may be degraded.
The followings are reference documents.
[Document 1] Japanese Laid-open Patent Publication No. 10-334981, and
[Document 2] Japanese Laid-open Patent Publication No. 2011-244247.